The immune response to the HIV involves an "autoimmune" component in which the patient makes both anti-HIV antibody as well as anti-HLA antibody. This type of response can also be seen in other viral infections which can cause immune deficiencies. During an HIV infection it appears that the older patients suffer a more extensive loss of T helper cells and reach lower levels more rapidly than do younger patients. Younger HIV infected patients can actually go through extended periods in which their CD4+ cell level remains in the normal range.